The invention is directed to a single-layer or multiple-layer surface foil or film based on a thermoplastic plastic for laminating on wood, plastic, metal or other substrates and having a colored, colorless and/or patterned base foil. The inventive foil may contain auxiliary processing agents, coloring agents, stabilizers and other conventional additives.
A surface foil of the type described above is known, for example, from EP-A-0 343 491. It is applied to the surfaces of objects such as doors, frames and housings made of plastic, wood, wood-containing products, metals or the like, including work materials or substrates in colored, colorless and/or patterned form to provide protection against corrosion, discoloration by light or mechanical influences, and the like. It is also used, as the case may be, to give the surface a more attractive appearance. For example, a patterned foil of this kind when laminated on a surface can present the appearance of valuable wood, even when using a starting material not actually suitable for this purpose owing to its quality, texture, surface or color.
The surface foil shown in EP-A-0 343 491 has a base layer made of a polymer of the methacrylate group. The polymer can be modified by adding polyacrylates. A polymethyl methacrylate (PMMA) which is rendered flexible by polybutyl methacrylate (PBMA) is particularly suitable. The known surface foil shows an improved resistance to light and weather. However, tests performed on this foil have shown it to be in need of improvement. For example, PMMA which is rendered flexible exhibits a relatively high degree of white crackling. Even when this material is adjusted so as to be impact-resistant, it provides only a low notched bar impact strength. Further, its wettability and surface tension values are unsatisfactory. High surface tension values are important for the printability of the base foil as well as for its bonding properties (adherence between an adhesive layer and the base foil) if this base foil is to be glued to a substrate. For example, a base foil made of PMMA has a surface tension of only 36 to 38 dyn/cm (measured according to DIN 53 364).